Hi Brian Goldman,
Currently OpenAccess ORM is not able to fully utilize web sites and web applications. What that means is that you cannot have directly the model classes inside a web site or web application, instead it should be placed inside a library project. That project is to be referenced then by the web site. You can find more about it here. After you have the project referenced by the web site, the combobox will be populated with the valid connection options from the projects, and you will only have to select what is required.
the Telerik team